The Vibrational Spectra and Structure of Inorganic Molecules. III. The Infra-Red Spectra of Nitrosyl Chloride and Nitrosyl Bromide from 2.0 to 25μ

Abstract

The infra-red absorption spectra of nitrosyl chloride and nitrosyl bromide vapors have been examined from 400 to 5303 cm−1, and the spectra explained on the basis of three fundamentals at 1799, 592, and 332 cm−1 for NOCl and 1801, 542, and 265 cm−1 for NOBr. The force constants and the amplitudes for the fundamental modes were calculated for a central force system. The P—R separation of the predominantly parallel bands and the spacing of rotational bands in one partially resolved mainly perpendicular band in the NOCl spectrum were found to be in good accord with the electron diffraction data for the dimensions of the molecule. Thermodynamic functions for the gases were calculated from 298° to 1500°K. The calculated values of S298° for both gases are in good agreement with the experimental values.